Exception events are user actions that stop triggered messages because they indicate that the user has already reached the desired goal.
In a triggered message campaign, exception events are the actions that users take that indicate they have already reached the desired goal, and as a result they do not receive the triggered message. For example, when setting up a reminder message to trigger when users fail to update their profile, you would want to indicate that if they come back a little later and actually complete the profile (exception event) they should not receive the reminder. This works together with a message delay to allow for a little time to complete actions before the triggered message is sent. Exception events help to make sure the triggered message is still relevant to the user.
“I’m so glad we created the exception event to catch users who had already updated their preferences—this time we won’t get feedback from annoyed users!”